Arthritis, more particularly osteoarthritis (OA), is a degenerative joint disease commonly occurring in humans and in companion animals. OA involves progressive deterioration of articular cartilage, with loss of proteoglycan and collagen and proliferation of new bone, accompanied by a variable inflammatory response within the synovial membrane. It is the most common form of joint and musculoskeletal disease affecting dogs, but cats may also suffer from this condition.
Feline OA is disease primarily affecting aged felines 10 years of age or older. Animals suffering from this disease characteristically jump less, reduce the height of their jumps or stop jumping entirely, avoid going up or down stairs, and tend to use their litter box less. Cats with OA also appear to be less friendly, exhibit changes in their sleep-wake patterns, and may have grooming problems. The management of OA in cats is similar to treatment regimens in other species which include environmental modification, treatment of obesity, controlled moderate exercise, pain control, and surgery.
Environmental modification begins with the placement of food bowls and litter pans in locations that do not require leaping or stair climbing. Small ramps can be built to a feeding station or into the litter box. The attempt is made by the pet owner to reduce large leaps up or down, to encourage moderate exercise, and to create an environment where the cat is not faced with an obstacle course to maintain a daily routine. Environmental modification does not slow the progression of the disease.
Overweight cats with OA can benefit from weight control. A reduction in body weight will alleviate the pressure and pain on the affected joint(s). Though weight loss in overweight or obese cats can help alleviate the pain caused by OA, it does not stop the progression of the disease.
Pain control in cats is a problem because drug regimens that are safe in other species are not necessarily safe in cats. Though many pharmaceutical companies are evaluating non-steroidal anti-inflammatory drugs (NSAIDs) in cats for treatment of pain, aspirin is the only NSAID for which a safe, chronic dose has been established in the cat. Corticosteroids have been used to alleviate pain and inflammation, but their use may cause progression of OA. NSAIDs may help alleviate pain but will not alter the progression of OA.
Nutraceuticals have been used to alleviate pain associated with OA in cats. Chondroitin sulfate and glucosamine HCl used in combination or separately have been used as a treatment regimen in cats. There are no published clinical studies that indicate these nutraceuticals alter the progression of OA. Recent data in humans indicates that chondroitin and glucosamine may help alleviate pain in humans with severe OA.
Although helpful in some respect to provide symptomatic relief, the approaches described above are not entirely successful in disease management, as they clearly do not treat the underlying pathology. Indeed, not only are improved treatment methods needed, but also improved methods to monitor the clinical progress of an animal with OA and even to diagnose an animal that has OA, and those that may be genetically predisposed to developing OA but do not as yet display any clinical signs of the disease. Currently, extensive radiographic tests must be carried out to confirm a diagnosis of OA in an animal and these tests are useful only to identify animals that have manifest joint and tissue damage. Thus, there is a need for a simple diagnostic test for detecting OA in felines, as well as improved methods for monitoring the clinical progress of an animal with OA.